Prince Harry fears his girlfriend Meghan Markle will be driven away by the intense scrutiny to which she has been subjected, friends have said, as he issued an unprecedented plea for "racist and sexist" online trolls to leave her alone.

The Prince, 32, accused mainstream and social media of “crossing a line” in commenting on their relationship as he warned: “This is not a game.”

Watch | Harry takes exception to 'wave of abuse' against his girlfriend

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The statement was the first official confirmation from Kensington Palace that the Prince is in a relationship with the American actress. It also said the couple have been together for "a few months".

Until now, Kensington Palace had adopted a strict "no comment" policy on all inquiries about 35-year-old Miss Markle, refusing to confirm or deny anything that was put to aides.

Miss Markle launched her own clothing range last weekCredit:
Instagram

But the Prince felt he finally had to speak out because “a wave of abuse and harassment" in recent days meant “it was no longer tolerable for his voice not to be heard on this”, according to insiders.

At the same time, Miss Markle contacted the UK media through her solicitors to ask that her privacy be respected.

Kensington Palace has issued a statement this morning about the harassment currently being experienced by Meghan Markle and her family. pic.twitter.com/EuFZ4fmUIj

Prince Harry was particularly upset by a “smear” on the front page of a national newspaper, understood to be an article last Friday reporting that clips of Miss Markle’s sex scenes from the US legal drama Suits had been uploaded to a pornographic website. He also took exception to an article published today speculating on the reasons for his girlfriend’s 2013 divorce from film producer Trevor Engelson.

The Prince was outraged by what he described as “the racial undertones of comment pieces and the outright sexism and racism of social media trolls and web article comments". Miss Markle has a black mother and a white father and has talked in the past about being a victim of racism.

“If this is the price someone has to pay for being Harry’s girlfriend, why would they do it?” said the source. “He is not naive, he knows he is not waving a magic wand and he knows articles will still be written about her, but he is not prepared to accept a campaign to destroy her reputation.”

Meghan Markle plays the character of Rachel in the US legal drama SuitsCredit:
USA Network

The Prince’s last long-term relationship, with the model and actress Cressida Bonas, was killed off by the constant attention Miss Bonas received when she was out in public, but the Prince feels Miss Markle’s situation is “worse than anything before”, a source said.

He believes that two factors are to blame - the changing media landscape, with the ever-increasing influence of social media, and the fact that at his age, every girfriend is inevitably regarded by the public as a possible bride.

“He wishes he wasn’t having to do this,” said the source, “but he doesn’t have a choice. It has gone from zero to 100 in eight days.”

While recognising that there is "significant curiosity about his private life" the Prince pleaded with all forms of media to step back “before any further damage is done”.

Miss Markle attended Wimbledon in the summerCredit:
Karwai Tang

His statement says: “Prince Harry is worried about Ms Markle’s safety and is deeply disappointed that he has not been able to protect her. It is not right that a few months into a relationship with him that Ms Markle should be subjected to such a storm.

"He knows commentators will say this is ‘the price she has to pay’ and that ‘this is all part of the game’. He strongly disagrees. This is not a game, it is her life and his."

The actress is reported to have visited him several times at Kensington Palace, and the Prince spent almost a week staying in Toronto with Miss Markle earlier this month.

Contrary to some reports, however, she has not met the Duke and Duchess of Cambridge, nor has she met the Prince of Wales or spent time at Balmoral.

The timing of the statement suggests that Miss Markle, who finishes filming the current series of Suits next week, may be planning another visit to London later this month, and the Prince perhaps wants to lay down a marker before she gets here.